bor·der·line 
(bôrdər-līn′)
(bôrdər-līn′)n.
1. A line that establishes or marks a border.
2. An indefinite area intermediate between two qualities or conditions: The borderline between love and hate is often thin.
3. Informal A person with borderline personality disorder.
adj.
1.
a. Verging on a given quality or condition: borderline poverty.
b. Of a questionable nature or quality: an applicant with borderline qualifications.
2. Psychiatry Of, related to, or having borderline personality disorder.